1. Field of the Invention
The present invention relates to techniques for displaying text securely (i.e., such that the displayed information cannot be copied by taking pictures of the display using a still or video camera). The techniques of the invention can be applied to display panels, such as hand-held and cell-phone displays, monitors, etc., which employ LCD panels, CRT screens or other display technologies that have a sufficiently high refresh rate.
2. Description of the Related Art
Hand-held devices with displays and laptops have become quite popular and in fact are now ubiquitous. Their popularity is due in part to the ease of which these devices can be deployed nearly anywhere including in public places. Viewing the display of such a device in a public place, particularly a crowded one, is not without risk, however, particularly if the information being viewed is confidential or private. The danger is that a stranger nearby may be able to view or copy information on the display. Prevention of such intrusive action is clearly desirable.